Fluid regulating device



Patented Mar. 2, 1948 FLUID REGULATING DEVICE Carl Oscar Josef Montelus, Stockholm, Sweden,

assignor to Aktiebolaget Imo-Industri, Stockholm, Sweden, a corporation of Sweden Application June 2, 1943, Serial No. 489,344 In Sweden May 20, 1942 1 Claim. 1

The invention relates to a device for regulating the quantity of fluid in two circuits in a certain predetermined proportion relative to each other, and is specially adapted for workshop machinery, aeroplanes, etc., where two or more pistons or other apparatus shall be moved with predetermined speeds or to predetermined distances. It is previously known to make such a device containing a movable piston valve, which by its movement regulates the proportion of fluid flowing to two different passages.

More particularly, it is the object of my invention to provide a more accurate regulation of the flow than has been possible with the `known devices and at the same time to make an apparatus which regulates not only the division of flow from a common piping into two different pipings, but also the return flow from these pipings in the opposite direction to the common piping. To these and other ends appearing hereinafter, my invention consists of the combination, location, construction and arrangement of the various` parts, all as more fully explained in the following vdescription and specifically pointed out in the claim.

In brief, these results are accomplished by the use of proportional metering or motor devices in combination with regulatory means for maintaining the pressure gradients across said devices substantially constant or preferably equal. If iiuid is fed in parallel to a plurality of mechanically connected motors ofV positive type, the .discharges from said motors should theoretically be in denite proportions to each other depending upon the relative displacements of the motors which will thus act as metering devices. However. any positive motor is such only to the degree to which leakage can be avoided. If the pressure gradients across two such positive motors are diiferent, the actual ow through the respective motors will depart from the theoretical to an extent depending upon the dierences in the pressure gradients. To produce definite proportioning through the motors. therefore, to eliminate the variable factor of leakage, it is necessary to maintain across them definite fixed pressure gradients either equal or constantly definitely related to each other. In accordance with the present invention, motors arranged as just indicated are associated with devices designed to maintain constant or equal presure gradients despite diierences of pressure which may arise in the system to which the iluid is being delivered. In brief, this is accomplished by causing selective throttling ofthe portions of fluid delivered from Y the regulating device.

the motors, the throttling being increased in the line from a motor at the discharge of which a lowered back pressure appears, thereby to increase such back pressure and secure, for example, its equality with the back pressure existing on the other motor or motors.

In the accompanying drawings, Fig. 1 is a sectional view of the device; Fig. 2 is a cross section to a larger scale along the line II-IL Fig. 1; Fig. 3 is a sectional view along the circle III in Fig. 2, this view being expanded in a plane; and Fig. 4 is a partial section along the line IV, Fig. 1.

Referring to the figures by characters of reference, I designates a common piping connected to The flow of fluid from this piping shall be divided into two portions to be transported from two different pipings 2 and 3, which portions should be exactly alike independent of the pressures in the pipings 2 and 3, or, on the other side, when the flow from these pipings which may be used to move hydraulcal pistons or other apparatus, is reversed, the device is designed to regulate the return ow in a similar way.

In a common casing 4, there is made an axial bore 5 which is closed at the ends by means of plugs 6 and 'I screwed into the casing. In the bore 5, a piston 8 is arranged so that it fits exactly but may be easily moved. In another bore 9 which consists of three parallel, intersecting cylindrical bores, a set of three screws is tted. These screws consist of a central power screw I9 and two idler screws Ita and Iilb, one on each side, said idler screws cooperating in a known way with the power screw lil so as to constitute two positively operating hydraulic motors driven by the flow of fluid. Thev power l screw I0 has convex helical surfaces, while the cooperating idler screws Illa, and Ib being made with concave helical surfaces. Each screw has two screw grooves and is divided in two portions comprising left-hand threads and righthand threads,lrespectively, each of the said portions constituting a hydraulic motor. The motors so provided are of the type described in my prior YPatents 1,698,802, dated January l5, 1929, 1,821,523, dated September 1, 1931, and 1,965,557, dated July 3, 1934, to which reference may be made for details of construction and operation. The central portion I I of the screws, which is not threaded, is through an opening I2 connected to the common piping I. The ends I3 of the central screw I Il are limited in their movement by the plugs I4 and I5, which are screwed into the casing 4. From the chambers I6 and Il at the 'chamber 2 I.

ends of the said screws, two bores I8 and I9, respectively, are cut to the chambers 20 and 2I,'re spectively, located in the bore on opposite sides of the piston 8.

The piston 8 has four axial bores or passages 22, 23, 24, 25 provided with non-return valves 26, 21, 28 and 29, respectively, said valves being constituted by spring-actuated balls (Fig. 3). The non-return valves are arranged in a manner such that the fluid in the passages 22 and 24 can flow upwardly only as viewed in Figs. 1 and 3, while in the passages 23 and 25 the fluid can flow downwardly only. The passage 23 is at its lower end closed by a plug 33. A similar plug 3l closes the upper end of the passage ZII.`

In the b-ore 5, there are provided two annular grooves 32 and 33, which through radial openings 34 and 35 are in open communication with the pipings 3 and 2, respectively. Each of the axial passages provided in the piston 8 communicates with a radial bore 36, 31, 38 and 39, respectively, by means of which said passages are connected to either of the grooves 32 or 33. As will be seen from Fig. 3, the bore 33 connects the p-assage 22 with the groove 32, and the bore 31 connects the passage 23 likewise with the groove 32, while the groove 33 communicates with the4 passages 25, and 25 by means of the bores 33 and 33, respectively. The radial bores 33, 31, 38 and 39 are arranged in a manner such that they in the intermediate position of the piston 3 shown in the drawing to half of their cross sectional area only directly communicate with the annular grooves 32 and 33. Consequently, at a displacement lof the piston 8 in the `one or other direction, the direct connection between two bores and the annular grooves will be increased, while at the same time the direct communication between the other two bores and the grooves will correspondingly be decreased. The movement of the piston in axial direction is limited by stop members 43 and 4I.

The device described operates as follows.

The ow of fluid supplied through the common piping I will be divided into two portionsimparting rotational movement to the set of screws IEl, Illa, Ib. TheV portions of the fluid will pass from the chambers I6, I1 through the bores I8, I9 to the chambers 23 and 2|, respectively. From the chamber 2i), the fluid will pass through the non-return valve 21 in the passage 23 and through theY radial bore 31 to the groove 32 and thence into the piping 3. In a similar way, the fluid from the chamber 2l will pass in the opposite direction through the non-return valve 28 provided in the passage 24 and through the bore 38 and the groove 33 into the piping 2. If now, for instance as a result of an additional resistance, the iiow of fluid through the piping 3 s obstructed, and, consequently, an increased quantity of fluid tends to flow through the piping 2, a pressure difference will be buiit at the rotation of the set of screws, with the result that the pressure in the chamber 2i! will be slightly increased above the pressure prevailing in the As arresult thereof, the piston 8 will be moved downwardly as viewed in Fig. 1 so that the direct communication between the passage 24 and the Ioore 38 and groove 33 will be throtted until a state of equilibrium will be restored with respect to the flow of the fluid portions. In a similar manner, the quantity of fluid passing through the bore 31 will be throttled upon increase of the resistance to the flow in the piping 2.

If the uid is flowing in the opposite direction, that is. from the separate pipings 2 and 3 to the common piping I, one of the :duid portions passes from the groove 33 through the bore 39, nonreturn valve 29 and passage 25 to the chamber piping 3 is increased for some reason lor other,

the pressure in the annular groove 32 will become lower than the pressure prevailing in the groove 33. The increased quantity of fluid which in this cas-e passes from the groove 33 through the bore v33 and the passage 25 to the chamber 2| will result in thatthe pressure .in the chamber 2I will be increased as compared with the pressure prevailingin the chamber 20. As a result thereof, the piston 8 will -be moved upwardly as viewed in Figs. 1 and 3 so as to throttle the connection between the bore 39 and the groove 33, until the state of equilibrium is restored.

It will be understood that the invention is not limited to the embodiment shown and described by way of example only. If two or more devices of the kind described are used, it will be possible to divide a flow of nuid into more than two portions in certain predetermined proportions.

What I claim is:

A fluid regulating device comprising two positively operating hydraulic motors mechanically connected to each other, a common fluid piping connected to yone end of each of said motors, a cylinder, a piston movable in said cylinder, a conduit for connecting the other end of one of said motors with one side of said piston, a conduit for connecting the other end of the other one of said motors with the other side of said piston, two separate fluid pipings connected to said cylinder, the areas Iof connections of said pipings to the cylinder being controlled by said piston, four passages in said piston, one pair of said passages communicating with one of said conduits and one of said separate pipings. the other pair of said passages communicating with the other one of said conduits and the other one of said separate pipings, a non-return valve in each of said `passages, the non-return valves in each pair of passages being arranged to permit flow of fluid in opposite directions, and said piston being :irranged to be displaced in said cylinder in response to diierences in pressure on opposite sides of the piston to vary the cross-sectional area for the flow of fluid between said motors and -said separate pipings to increase throttling action upon flow through the motor having a lowered pressure occurring at its discharge, whereby to reestablish the normal proportion of iiow through said separate pipings.

CARL OSCAR JOSEF MONTELIUS.

REFERENCES CITED The following references are of record in the Great Britain 1932 

